His professional background was in civil engineering — and it was precisely that expertise that made him useful to the SS apparatus responsible for constructing the death camps of Operation Reinhard. Thomalla oversaw the building of facilities at Sobibór and Treblinka, sites that would become central to the murder of hundreds of thousands of Jews during the Holocaust. The administrative and technical competence he brought to that work placed him among those whose roles, though rarely examined in isolation, were structurally essential to industrialized killing.

His 1793 book arguing that the Atlantic slave trade was a mercy — sparing captives from ritual sacrifice — stands as one of the more calculated apologetics produced in defense of the trade during that era. Dalzel moved through its infrastructure with professional fluency: surgeon, governor, author, shipowner, and ultimately slave trader operating his own vessels. The ships he owned delivered nearly five hundred people to the West Indies, and he continued trading until British law compelled him to stop.

Operating across a concentrated stretch of Yekaterinburg over just a few months, Karimov built his access to victims through deception — posing as a tourist or a police officer — before carrying out attacks that varied enough in method to complicate early investigation. An earlier conviction for robbery and assault had done little to interrupt his trajectory. The survivors of his final attacks in March 2006 were ultimately what brought him to arrest and identification.